ISSN:0143-1161    

DOI:10.1080/01431169508954544

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

Coal fires are a ubiquitous problem in coal-mines, the world over. They burn our prime energy resource, lead to atmospheric pollution and render mining of coal hazardous. Processes leading to coal combustion and spread of subsurface fires are briefly examined in this paper and the role of remote sensing in surveillance of coal fires is presented.

ISSN:0143-1161    

DOI:10.1080/01431169508954545

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

For mapping and monitoring the spatial distribution of salt-alTected soils using remote sensing data, a thorough understanding of their spectral behaviour is of paramount importance. The spectral behaviour of a few typical salt-affected soils of the Indo-Gangetic alluvial plain was studied by taking ground-based spectral measurements with the Exotech radiometer (model 100 BX) and measurements made by the thematic mapper (TM) onboard Landsat-5. Salt-alTected soils, in general, showed relatively higher spectral response in the visible and near-infrared regions of the spectrum as compared to normal cultivated soils. Further, strongly saline-sodic soils were found to have higher spectral response as compared to moderately saline-sodic soils. The vegetation cover modifies the overall spectral response pattern of salt-affected soils especially in the green and red spectral bands. In addition, variation in the Sun elevation angle and moisture content were also found to modify the observed spectral response of salt-alTected soils. Methodology and results are discussed in detail.

ISSN:0143-1161    

DOI:10.1080/01431169508954546

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

A remote sensing analysis of the temporal changes of vegetation cover in the arid and semi-arid regions of the Judean Desert and Judean Mountains was carried out in order to reveal the controlling factor of the environmental system. Assessment of ditTerent combinations of temperal changes in the region using GIS techniques indicated that it is possible to differentiate between two major patterns of vegetation cover change. The classification of the region according to these patterns has produced a map that is highly correlated to the soil map of the region, thus suggesting that the soil is an important environmental controlling factor in the region. From the remote sensing point of view, the patterns of vegetation cover change may serve as indicators of soil types in similar arid and semi-arid environments.

ISSN:0143-1161    

DOI:10.1080/01431169508954547

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

The effects of surficial vegetation cover on the efficacy of automated absorption feature extraction and parameterisation of short-wave infra-red (SWIR) mineral absorption features is investigated. Synthetic spectral mixtures were generated from laboratory spectra of five SWIR absorbing minerals and live/dead vegetation. After convolution to the bandpasses of the Airborne Visible/Infra-Red Imaging Spectrometer the deepest absorption feature in each spectral mixture was extracted and parameterised in terms of wavelength position, depth, full width at half maximum depth, area and asymmetry. Live vegetation was found not to influence the wavelength position of mineral absorption features, conversely, dead vegetation induced abrupt and large shifts in wavelength position. Both live and dead vegetation reduce the depth of mineral absorption features, however, dead vegetation has the greatest impact on absorption features located at or near 2200nm. Dead vegetation was found to have a significant impact on the width, area and asymmetry of mineral absorption features.

ISSN:0143-1161    

DOI:10.1080/01431169508954548

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

Growing interest in urban systems as ecological entities calls for some standards in parameterizing biophysical composition of urban environments. A vegetation-impervious surface-soil ( V-I-S) model is presented as a possible basis for standardization. The V-I-S model may serve as a foundation for characterizing urban/near-urban environments universally, and for comparison of urban morphology within and between cities. Inasmuch as the model may be driven by satellite digital data, it may serve as a global model of urban ecosystem analysis and comparison world-wide. The V-I-S model may prove useful for urban change detection and growth modelling, for environmental impact analysis from urbanization, for energy- and water-related investigations, and for certain dimensions of human ecosystem analysis of the city as well.

ISSN:0143-1161    

DOI:10.1080/01431169508954549

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

Pairs of Landsat Multispectral Scanner System images from seven contrasting areas were analysed using scale variance analysis to determine the spatial frequencies present. Specifically images of the Normalized Difference Vegetation Index (NDVI) were analysed, which is sensitive to vegetation activity. Analyses were performed on images for each of the two dates and change images derived by subtracting the NDVI values of the first images from those of the second date. As expected the change images were characterized by higher spatial frequencies than the images of individual dates, but this was only marked for four of the seven areas. Contrary to initial expectations, knowledge of the spatial frequency content of the images from the two dates could not be used to infer the spatial frequencies present in the change images and hence the spatial resolutions needed for detecting change in the NDVI.

ISSN:0143-1161    

DOI:10.1080/01431169508954550

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

A study of the estimation of partial cloud cover within a pixel has been conducted in order to be able to use pixels partially contaminated with cloud in sea surface temperature determination.

ISSN:0143-1161    

DOI:10.1080/01431169508954551

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

Cloud cover is capable of generating mesoscale temperature gradients by shading the surface. The purposes of this paper are to utilize GOES visible imagery to assimilate cloud shading elTects into a mesoscale model and to examine the ability of a realistic treatment of moving and changing cloud fields to produce boundary layer convergence zones which may lead to preferred areas of deep convective development. A simplified version of the radiative model of Gautier et Ill. is used to convert hourly gridded GOES brightness data into surface insolation for assimilation into the mesoscale model. The conversion process is presented in detail so that readers may duplicate the assimilation scheme. A case in the Texas Panhandle on 24 and 25 April 1982 is studied. Results of the modelling study show that cloud shading produces (a) a much more complicated surface temperature field, (b) a large change in the planetary boundary layer depth, and (c) substantial boundary layer convergence zones compared to a simulation without cloud shading. These mesoscale effects, in association with synoptic-scale instability, may be important in thunderstorm and severe weather development. The techniques utilized for assimilating satellite-derived insolation may be especially important in after-the-fact mesoscale modelling of air pollution cases and in field studies.

ISSN:0143-1161    

DOI:10.1080/01431169508954552

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

It is very important to consider the illumination and observation geometry when satellite data are processed, i.e. to take into account all the angles in the radiation path. The importance of modifications introduced in the radiation and the geometric distortions of the image depends on the range of values of the angles. The angles related to the illumination geometry depend on the Sun's position relative to the sensor and the pixel being observed, while those related to the observation geometry depend on the radiometer characteristics. NOAA satellites carry the AYHRR sensor with an observation angle of ±56°, and their scanning line is approximately 2800km wide. For these satellites, the angular values involved in the illumination and observation geometry show an important gradient along the scanning line. The purpose of the present paper is to analyse in detail both the illumination and observation geometry. The results of such analysis were applied as an example using raw data of the NOAA–11–AYHRR images over theRio de la Plataand its ocean front region. As a part of the analysis and to improve the visual interpretation of the results, one-band synthetic images of the different illumination parameters were obtained. The results show that the large sensor field of view reduces the availability of the swath in after a few hundred kilometers. On the other hand, high latitudes should be excluded from the analysis, especially at winter solstice because of the large values of solar zenith angles. Different types of sporadic natural events that happened in the southern region of South America are also discussed, considering the results of the analysis and the purpose of enhancing the usefulness of AYHRR data in monitoring hazards. The phenomena considered were fires, volcano eruptions, and red tide blooms.

ISSN:0143-1161    

DOI:10.1080/01431169508954553

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor